A combined atomistic-continuum study on the temperature effects on interfacial fracture in SiC/SiO2 composites

Abstract

In this paper, for the first time, we combine reactive molecular dynamics and continuum fracture mechanics to investigate the effect of temperature on fracture behavior of a crack existing at the strong interface of SiC/SiO2 ceramic composite. At strong interfaces, existing cracks tend to propagate out of interface under mixed mode (i.e., combined opening/sliding) loading conditions. As temperature varies, the material properties change thereby affecting the interfacial crack propagation behavior. First, the temperature-dependent material properties of silicon carbide (SiC) and amorphous silica (SiO2) derived from ReaxFF reactive molecular dynamics simulations. Next, using a multi-scale modeling approach these temperature-dependent properties are used as inputs to the continuum-based model for investigating the fracture behavior as a function of temperature. By employing maximum tangential stress (MTS) criterion at the continuum scale, the effect of ambient temperature on the interfacial fracture toughness and crack kinking angle are studied. It was found that the ambient temperature significantly influences the mixed mode I/II kinking behavior for cracks existing at the SiC/SiO2 strong interface. The overall approach shows that reactive molecular dynamics combined with continuum model provide a more comprehensive modeling approach for examining fracture in ceramic composites with strong interface.